Method and apparatus for synchronizing the balance system of clocks or wrist watches

ABSTRACT

A watch pulse synchronizing circuit includes a transistor driver stage in a given circuit arrangement with a drive coil for a watch balance system and a transistor switching stage controlled by a sync pulse. The vibration frequency of the balance system is slightly higher or lower than one half of the sync frequency. The sync signal through action of the switching stage turns the driver stage on and off once for each half vibration of the balance system. Changes between the vibration and sync frequency changes the width of a primary pulse and generates a secondary pulse to charge a capacitor so that the sum of the energy of the two pulses remain constant for the output of the driver coil.

United States Patent [191 Keller et al.

[111 I 3,818,376 June 18, 1974 METHOD AND APPARATUS FOR SYNCHRONIZINGTHE BALANCE SYSTEM OF CLOCKS OR WRIST WATCHES Inventors: Hans Keller,Freiburg; Wolfgang Schultz, Waldkirch, both of Germany Assignee: lTTIndustries, New York, NY.

Filed: Feb. 16, 1973 Appl. N0.: 333,428

[30] Foreign Application Priority Data Mar. 4, 1972 Germany 2210542 US.Cl. 331/116 M, 58/23 A, 318/128, 331/172 Int. Cl G04c 3/00, H03b3/04,H03b 5/30 Field of Search 331/116 M, 172; 58/23 A, 58/23 AC, 28 A;318/128 References Cited UNITED STATES PATENTS 5/1970 Shelley et a1331/1 16 M X 3,618,311 11/1971 Wiesner et a1. 331/116M X PrimaryEraminer-Herman Karl Saalbach Assistant Eraminer-Siegfried H. GrimmAttorney, Agent, or Firm-John T. OHalloran; Menotti .l. Lombardi, Jr.;Alfred C. Hill [57] ABSTRACT driver stage on and off once for each halfvibration of the balance system. Changes between the vibration and syncfrequency changes the width of a primary pulse and generates a secondarypulse to charge a capacitor so that the sum of the energy of the twopulses remain constant for the output of the driver coil.

4 Claims, 5 Drawing Figures PAIENIEDJUNI 1w 3.818.376

' sum 10? 3 MAGNET TYPE R BALANCE SYSTEM MAGNET 7 2 L TYPE Q A BALANCE LSYSTEM 2 E A CRYSTAL K R2 OSCILLATOR AND fi- FREQUENCY L CRY5TAL DIVIDEROSCILLATOR I AND Fly-l y 5 FREQUENCY DIVIDER A/\ a) I V Fig.2

PATENTEDJUN 1 81974 SHEET 2 OF 3 zfo f PATENTEDJUHWW 3.818.378 SHEET 30F3 Fig.4

BACKGROUND OF THE INVENTION The step-by-step devices primarilyconsidered for use as electromechanical transducers for utility-typecrystal-controlled clocks and particularly for crystalcontrolled wristwatches are relatively sensitive to shock. Electromagnetically drivenbalance systems show a much better behavior in this respect.

The vibration frequency of a balance system depends on, among otherthings, the kind of energy supply. This fact, which is disadvantageousin itself, can be used to synchronize an electromagnetically drivenbalance system.

It is known, for example, from German published Patent Application 2,011,233 that a simple one or twocoil balance system driven automaticallyby a suitable circuit can be synchronized if, in addition to the maindrive pulse, one or more auxiliary drive pulses are applied which areshifted in time relative to the reference position of the balance systemand are triggered by the sync signal occurring several times during avibration of the balance system, i.e., the frequency of the sync pulsesis several times higher than that of the balance system vibration. Inthat method, however, more power than necessary is needlessly applied tothe balance sys tem through the auxiliary drive pulse, so that theamplitude of vibration of the balance system increases and the batteryis additionally loaded, while undesirable transient conditions occurduring the control.

On the other hand, it is known from Swiss published Patent Application12,571/67 that the vibration frequency of an electromagnetic balancesystem can be better synchronized if the drive coil is supplied with twosuccessive drive current pulses having a constant total energy content,one of which is applied before the reference position of the balancesystem, and the other thereafter, the vibration frequency of the balancesystem being changed as a function of the sync signal by variation ofthe relative amplitude values of the two pulses.

To enable a better terminological distinction, the sole drive pulseoccuring automatically with an unsynchronized drive circuit willhereinafter be referred to'as primary pulse, while the second drivepulse will be termed secondary pulse.

For the realization of the method of said Swiss Patent Application, acomplicated and expensive circuit is disclosed which comprises a bridgepush-pull stage, designed to drive the electromagnetic balance system,and two moving coils, which cannot be connected direct to one pole ofthe battery as is particularly desirable for a realization using,monolithic integrated circuit techniques. In addition, the bridgepush-pull circuit is not capable of maintaining the vibrations of thebalance system without the utilization of the circuit generating thesync signal. The complete circuit of the known kind operates on theprinciple of phase comparison between the vibration frequency of thebalance system and the frequency of the sync signal. It, therefore, hasseveral multivibrator stages and a sawtooth generator to achieve thephase comparison, which adds to the above-mentioned complexity. Inaddition, the

known circuit is tailored for a special coil and magnet,

system with two concentric pancake coils and a pair of magnetic poles inthe direction of vibration where in the coil legs located before andbehind the reference position one positive and one negative pulse isgenerated with each semi-vibration of the balance system, from whichfact the above-mentioned use of a bridge push-pull circuit follows ofnecessity.

SUMMARY OF THE INVENTION The present invention therefore relates to amethod of synchronizing, by means of the divided frequency of a crystaloscillator, the balance system of utility clocks, and particularly ofwrist watches, which, in the direction of vibration, preferably hasthree pairs of magnetic poles of alternating polarity, wherein, withoutsynchronization, the vibrations of the balance system are maintained byan automatic drive circuit through one drive pulse (primary pulse) persemi-oscillation, while, with synchronization, two successive drivecurrent pulses (primary pulse secondary pulse) having a total energycontent divided between them are applied per semi-oscillation to thedrive coil of the electromagnetic balance system.

Starting from the prior art, the present invention has for its object toprovide a method whereby the above described disadvantages of thearrangement disclosed in the above-mentioned German Patent Applicationcan be avoided. Use will be made of the principle of dividing the drivecurrent pulse at a constant total energy content of the divided drivepulses as disclosed in the above-mentioned Swiss Patent Application,with a view to considerably simplifying circuit arrangements suitablefor carrying out the method.

A feature of the present invention is the provision of a method ofsynchronizing a balance system of clocks and wrist watches having anautomatic drive circuit and a given vibration frequency comprising thesteps of: generating a sync signal having a given frequency, one half ofthe given frequency being slightly different than the given vibrationfrequency of the balance system; controlling by the sync signal theconduction of the drive circuit once per semi-vibration of the balancesystem in such a manner that the more the given vibration frequencydeparts from one half of the given frequency the more the energy contentof a primary pulse produced by the drive circuit is' reduced; andproducing automatically in the drive circuit a secondary pulse havingthe same polarity as the primary pulse as the energy content of theprimary pulse is reduced, the energy content of the secondary pulsebeing dependent on the energy content of the primary pulse, both theprimary pulse and the secondary pulse providing a constant total energycontent for the drive circuit.

Another feature of the present invention is the provi sion of a circuitarrangement to carry out the above method comprising: a circuit toproduce a sync signal; a driving transistor of given conductivity type;a control transistor of a conductivity type complementary the givenconductivity type; a balance system; a supply voltage source having apositive pole and a negative pole; a drive coil for the balance systemhaving one end thereof coupled to one of the poles of the source; afirst resistor coupled between the other end of the drive coil and thecollector of the driving transistor; the emitter of the drivingtransistor being coupled to the other of the poles of the-source; acapacitor having one plate thereof coupled to the one of the poles ofthe source;

a second resistor coupled between the other plate of the capacitor andthe junction of the drive coil and the first resistor; the emitter ofthe control transistor being coupled to the other plate of thecapacitor; a third resistor and a fourth resistor coupled in seriesbetween the other of the poles of the source and the junction of thedrive coil and the first and second resistors; the base of the controltransistor being coupled to the junction of the third and fourthresistors; the collector of the control transistor being coupled to thebase of the driving transistor; an auxiliary transistor of aconductivity type complementary to the given conductivity type, thecollector of the auxiliary transistor being coupled to the other of thepoles of the source, the emitter of the auxiliary transistor beingcoupled to the other plate of the capacitor and the base of theauxiliary transistor being coupled to the junction of the junction ofthe driving coil and the first and second resistors; and an additionaltransistor having its base coupled to the circuit to produce the syncsignal and its collector-emitter path inserted at a given point in thecircuit arrangement to control the conduction of the driving transistor.

A further feature of the present invention is the provision of a circuitarrangement to carry out the above method comprising: a. circuit toproduce a sync signal; a supply voltage source having a positive poleand a negative pole; a balance system; a transistor having itscollector-emitter path coupled to one of the poles of the source; aoperating coil for the balance system disposed in the collector-emittercircuit of the transistor; a control coil for the balance system; aself-starting network including a resistor coupled between the one ofthe poles of the source and the base of the transistor, and a capacitorcoupled in series with the control coil in the base-emitter circuit ofthe transistor; and an additional transistor having its base coupled tothe circuit to produce the sync signal and its collector-emitter pathinserted at a given point in the circuit arrangement to control theconduction of the transistor. v

The invention is based on the discovery that most conventional oneandtwo-coil circuits for driving electromechanical balance system can besynchronized without transient conditions and within a wide range if oneof the current paths of the circuit is turned on and off or off and onby the sync signal instead of carrying out a complicated phasecomparison or only applying or triggering a falsely positionedadditional pulse as is the case in the prior art circuits. It isparticularly advantageous if the sync-signal duration for which thecurrent path of the automatic drive circuit is on or off isapproximately equal to the duration of the voltage induced in thecontrol coil during a semi-vibration.

BRIEF DESCRIPTION OF THE DRAWING cuit for carrying out the method inaccordance with the principles of the present invention;

FIG. 2 illustrates, for the two possibilities and their signs, thevoltage induced in the drive coil of FIG. 1

during one vibration of the balance system;

FIG. 3 illustrates the sync signal and the voltage waveform across thedrive coil at three different balance frequencies for positive inducedvoltage;

FIG. 4 illustrates the sync signal and the voltage waveform across thedrive coil at three different balance frequencies for negative" inducedvoltage; and

FIG. 5 is a schematic diagram of a conventional, selfstarting two-coildrive circuit for carrying out the method in accordance with theprinciples of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates the one-coildrive circuit disclosed in the copending application of H. Keller and W.Sauer, Ser. No. 227,369, filed Feb. 18, 1972 now US. Pat. No. 3,742,385which, by addition of a further transistor whose base is fed with thesync signal, was expanded so as to be suitable for carrying out themethod in accordance with the principles of the present invention.However, a further transistor may also be added to most of the otherknown one-coil drive circuits containing a capacitor so thatsynchronization by a crystal oscillator with following frequency divideris made possible.

The drive circuit shown in FIG. 1 contains only the coil L, which actsas an operating and control coil. Superimposed on the voltage which isinduced in coil L by the magnet system of balance system 1 and whosewaveform, generated by a three-magnet system, is shown in FIG. 2 for acomplete vibration of the balance system is the drive pulse generated bythe circuit, as is shown in FIG. 31). One end of the coil L is connectedto one pole of the supply voltage source U, while its other end isconnected via resistor R3 to the collector of the driving transistor T1,whose emitter is in turn connected to the other pole of supply voltagesource U. The base of driving transistor T1 of the npn conductivity typeis connected to the collector of the control transistor T2, which iscomplementary to the driving transistor (i.e. of the pnp conductivitytype) and whose emitter is connected through capacitor C to one pole ofsupply voltage source U. The emitter of control transistor T2 isconnected via resistor R4 to the junction point of coil L and resistorR3. This junction point is connected via the voltage divider consistingof resistors R1 and R2 to the other pole of the supply voltage source U,while the junction point of the two resistors R1 and R2 has the base ofthe control transistor T2 connected thereto. The complementary auxiliarytransistor T3 (i.e. of the pnp conductivity type) has its base connectedto the junction point of coil L and resistor R3, while its collector isconnected to the other pole of supply voltage source U. The emitter ofthe auxiliary transistor T3 is connected to the emitter of the controltransistor T2. This one-coil drive circuit is capable of maintaining thevibrations of the balance system automatically.

The current path to be turned on and off by the sync signal may beprovided at any point of the circuit, as required. Particularly wellsuited for this purpose is each of the three lines connected to theelectrodes of each of the two transistors T1 and T2. It is, however,also possible to use either of the two lines connected to supply voltagesource U from the circuit as the current path to be turned on and off bythe sync signal.

In the embodiment of FIG. 1, the base current path of driving transistorT1 is turned on and off at the common junction point of the base ofdriving transistor T1 and the collector of control'transistor T2 by anadditional transistor T4 of the npn conductivity type, which acts as aswitch controlled by the sync signal, connected between said commonjunction point and the other pole of the supply voltage source U. Thesync signal is produced by a crystal controlled oscillator and frequencydivider 2 which may take the form disclosed in the copending applicationof H. Keller and W. Kreitz, Ser. No. 290,919, filed Sept. 22, 1972. Theemitter of additional transistor T4 is connected to the negative pole ofthe supply voltage source, and its collector is connected to said-common junction point, while its base, serving as the input E, issupplied with sync signal. Hence, the inventive turning-on and -off of acurrent path also comprises rendering a current path of the circuitinoperative by means of a short circuit to be opened or closed andconnected in parallel to the current path, as is shown in FIG. I for thebase-emitter path of driving transistor T1.

As already mentioned, FIG. 2 shows the voltage induced in coil L by athree-magnet system during one vibration of the balance system. Thebroken vertical line gives the reference position of the balance system.The balance system passes through this reference position twice pervibration. This induced voltage comprises a positive and a negative mainpeak and a positive and a negative secondary or satellite peak.

FIG. 2a shows the induced voltage referred to above as positive. Aninduced voltage is defined as positive if the first secondary peakrelative to time and the second main peak relative to time are positive.An in duced voltage is defined as negative if the first secondary peakrelative to time and the second main peak relative to time are negative.This induced voltage is shown in FIG. 2b.

The use of a three-magnet system requires that in both thecounterclockwise semi-vibration and the clockwise semi-vibration of thebalance system the same pulse shape of the induced voltage is generated,as is shown in the two respective identical wave patterns of FIG. 2a andFIG. 2b.

In the method according to the present invention, the frequency of thesync signal f, is chosen to be about twice as high as the vibrationfrequency f, of the balance system, as shown in FIGS. 3 and 4. In FIGS.3a and 4a, the output pulse of crystal oscillator and frequency divider2 is illustrated as the sync signal. The frequency divider usuallyconsistsof series-connected, bistable flip-flop stages and divides theoscillator frequency by a number corresponding to a power of two, withthe exponent corresponding to the number of stages. Such bistableflip-flop stages deliver at their outputs a square-wave signal with aunity mark-to-space ratio, as shown in FIGS. 3a and 40.

It is not absolutely necessary, however, that the sync signal have aunity mark-to-space ratio. Other mark-tospace ratios may be chosenprovided that is is insured that the duration of the sync signals pulseportion turning the current path on or off is approximately equal to theduration of the voltage induced in the coil during one semi-vibration.

FIGS. 3!) to 3d show, for positive induced voltages and for differentcases of the numerical relationship between the frequency f, of the syncsignal and the vibration frequency f, of the balance system, waveformsdeveloped when the method in accordance with the present invention iscarried out. In the present case it is assumed that the balance system,without any sync signal acting upon the circuit, has a natural frequencyf, which results in a positive-going rate of the clock, i.e., whichcauses the clock to be fast. Thus, without sync signal, the vibrationfrequency of the balance system has been chosen to be slightly higherthan one-half the frequency f, of the sync signal. The voltage pulsethen appearing across the coil L is shown in FIG. 3c. In this case, thevoltage drop caused across the dc. (direct current) resistance of thecoil by the primary and secondary pulses is superimposed on the inducedvoltage. The interrelationship of positive induced voltage and gainingbalance system must be employed if, as in the circuit of FIG. 1, thedriving transistor is of the npn conductivity type and if, consequently,its emitter is connected to the negative pole of the supply voltagesource. With a driving transistor of the pnp conductivity type, which,of course, is also possible and whose emitter would have to be connectedto the positive pole of the supply voltage source, and with positiveinduced voltage, the balance system would then be slow.

Due to the higher repetition frequency of the induced voltage pulsesrelative to the sync signal, the waveform of the induced voltage asshown in FIG. 30 is shifted to the left relative to the synchronouscondition of FIG. 3b. Since, in the circuit of FIG. 1, the sync signal,if positive, turns the base current path of the driving transistor off,the primary pulse I, which, without synchronization, would be possibleat an earlier instant relative to the induced voltage, cannot occuruntil after the current path has been turned on again, i.e. after theinduced voltage has become more negative than that of FIG. 3b.

Since, however, after the triggering of the primary pulse I, the circuitacts independently of the sync signal, the primary pulse I is endedafter the induced voltage has exceeded a threshold value predeterminedby the design of the drive circuit, i.e., the primary pulse I of FIG. 30has a smaller width and, consequently, a lower energy content than thatof FIG. 3b.

As a result of the smaller width of the primary pulse I, however, thecapacitor C could not be charged through auxiliary transistor T3 to theextent shown in FIG. 3b, so that a secondary pulse II is generated whosewidth depends on the charging condition of capacitor C and which is ofthe same polarity as the primary pulse I. In the case of FIG. 3b,however, the capacitor C has been charged through auxiliary transistorT3 by the primary pulse I to such an extent, and thus the threshold ofresponse of the control transistor T2 has been shifted to such anextent, that a second drive pulse can no longer be generated.

FIG. 3d shows the case where the balance vibration j", is even higherthan in the case of FIG. 3c. In the case of FIG. 3d, the balance systemvibrates so fast that the sync signal does not enable the circuit todeliver the primary pulse I until the induced voltage has exceeded itsnegative peak value. Therefore, the primary pulse I is very narrow.Since, in the case of FIG. 3d, the capacitor C has been charged by thenarrow primary pulse I even less than in the case of FIG. 3c, thesecondary pulse II is correspondingly wider.

FIGS. 4b to 4d show the corresponding waveforms for a negative inducedvoltage. In this case, the balance system has a natural frequency whichresults in a negative-going rate of the clock, i.e. which causes theclock to be slow. Thus, the vibration frequency f of the balance systemis chosen to be slightly lower than one-half the frequency f, of thesync signal. Due to the lower repetition frequency of the inducedvoltage pulses, the

' waveform of the induced voltage as shown in FIG. 4c

is shifted to the right relative to the synchronous condition of FIG.4b. Therefore, the primary pulse I is ended by the sync signal earlierthan in the free-running condition of the drive circuit, i.e., theprimary pulse I has a smaller width and, consequently, a lower energycontent than that of FIG. 4b.

Here, too, similarly to the cases described with reference to FIG. 3,the reduction of the energy of the primary pulse I results in theoccurrence of a secondary pulse II, whose width depends on the width ofthe primary pulse I in a mirror-inverted manner relative to timecompared with the cases of FIG. 3, i.e., the secondary pulse IIassociated with a pulse of the induced voltage is linked with theprimary pulse I associated with the previous pulse of the inducedvoltage to cause a division of the energy content of the total drivepulse. The interrelationship of negative induced voltage and losingbalance system must be employed if, as in the circuit of FIG. 1, thedriving transistor is of the npn conductivity type and if, consequently,its emitter is connected to the negative pole of the supply voltagesource. With a driving transistor of the pnp conductivity type, which,of course, is also possible, and whose emitter would have to beconnected to the positive pole of the supply voltage source, and withnegative induced voltage, the balance system would be fast.

FIG. 5 shows a conventional two-coil drive circuit which is capable ofstarting by itself via an RC (resistorcapacitor) network and can also besynchronized by the method in accordance with the present invention. Thecircuit comprises the transistor T, which amplifies the pulses generatedby the magnet system of balance system 1 in the control coil L, andcauses these pulses to become effective in the operating coil L Thus,the operating coil L also coupled to balance system 1 is located in theoutput circuit of the transistor. In the embodiment of FIG. 5, coil L isinserted in the emitter line of transistor T with one end of coil Lbeing connected to the emitter of transistor T. One end of control coilL, is connected to the emitter of transistor T, while its other end isconnected via the capacitor C to the base of transistor T. Thus, coil L,is located in the input circuit of the transistor T. The base oftransistor T is also connected via the resistor R to one pole (-l-) ofthe supply voltage source U and the collector of the transistor T isconnected to this pole direct. If the other end of coil L, is connectedto the other pole of supply voltage source U, the conventional two-coildrive circuit with self-starting RC-network is obtained such as is knownin principle from FIG. 1 of French Patent 1,376,358. If the balancesystem is at rest, this circuit, by charging capacitor C throughresistor R, is capable of generating a drive current pulse in operatingcoil L which causes the balance system to start from standstill, becausecapacitor C is charged until the threshold voltage necessary to rendertransistor T conductive is reached.

In the embodiment of FIG. 5 there is also provided additional transistorT4, whose collector-emitter path is inserted between that end ofoperating coil L, which is remote from the emitter of transistor T, andthe negative pole of the supply voltage source U, while its base servesas the input E for the sync signal from crystal osare the same as in thearrangement of FIG. 1, whose operation was described in connection withFIGS. 3 and 4, with the only exception that here, in the case of apositive sync signal, the current path is not turned on and off.

In the arrangement of FIG. 5 it is also, of course, possible to placethe additional transistor at any other point of the two-coil drivecircuit, i.e., in two-coil circuits, so that the current path to beturned on or off by the sync signal can be chosen as required.

Maintaining the principle underlying the present invention, the methodin accordance with the invention can also be used in clocks with magnetsystems which have a greater or smaller number of poles.

It is particularly advantageous if all electronic circuit parts are madeusing monolithic integrated circuit techniques. It is possible toprovide both a single integrated circuit, comprising the automatic drivecircuit and the frequency divider stages, in one enclosure and severalindividual integrated circuits in several enclosures for the individualcircuit parts. In the latter case it is possible, for example, to makeone part, mainly the frequency divider stages, as a monolithicintegrated circuit using insulated gate field effect transistors (MOS- Fet), while the other parts are made as monolithic integrated circuitsusing bipolar transistors. However, other distributions to MOS andbipolar techniques are possible, also.

The essential advantage of the method in accordance with this inventionis that a crystal-controlled clock can be derived in a simple mannerfrom a clock with electromagnetic balance drive by only providing anadditional electronic unit comprising the crystal oscillator and thefrequency divider, but without any structural changes in the movement,and that such a crystal controlled clock can be mass-produced. Asynchronization range of more than :3 min/d is easy to achieve, so thateven extreme changes in the natural frequency of the balance system canbecorrected. Another advantage of the method in accordance with thisinvention is that, with the kind of synchronization in accordance withthe invention, the vibration amplitude of the balance is kept constant,so that the synchronization can cause no control oscillations. Inaddition, the vibration amplitude of the balance system can be chosen tobe large (e.g. 200), so that the torques exerted on wrist-watch balancesystems due to motions of the hand or of the arm have only littleeffect.

While we have described above the principles of our invention inconnection with specific apparatus it is to be clearly understood thatthis description is made only by way of example and not as a limitationto the scope of our invention as set forth in the objects thereof and inthe accompanying claims.

We claim:

1. A circuit arrangement for carrying out a method of synchronizing abalance system of clocks and wristwatches having an automatic drivecircuit and a given vibration frequency comprising the steps of:generating a sync signal having a given frequency, one half of saidgiven frequency being slightly different than said given vibrationfrequency of said balance system; controlling by said sync signal theconduction of said drive circuit departs from one half of said givenfrequency the more the energy content of a primary pulse produced bysaid drive circuit is reduced; and producing automatically in said drivecircuit a secondary pulse having the same polarity as said primary pulseas the energy content of said primary pulse is reduced, the energycontent of said secondary pulse being dependent on the energy content ofsaid primary pulse, both said primary pulse and said secondary pulseproviding a constant total energy content for said drive circuit; saidcircuit arrangement comprising:

a circuit to produce said sync signal; a driving transistor of givenconductivity type; a control transistor of a conductivitytype'complementary to said given conductivity type; a balance system; asupply voltage source having a positive pole and a negative pole; adrive coil for said balance system having one end thereof coupled to oneof said poles of said source;

a first resistor coupled between the other end of said drive coil andthe collector of said driving transistor;

the emitter of said driving transistor being coupled to the other ofsaid poles of said source;

a capacitor having one plate thereof coupled to said one of said polesof said source;

a second resistor coupled between the other plate of said capacitor andthe junction of said drive coil and said first resistor;

the emitter of said control transistor being coupled to said other plateof said capacitor;

a third resistor and a fourth resistor coupled in series between saidother of said poles of said source and the junction of said drive coiland said first and second resistors;

the base of said control transistor being coupled to the junction ofsaid third and fourth resistors;

the collector of said control transistor being coupled to the base ofsaid driving transistor;

an auxiliary transistor of a conductivity type complementary to saidgiven conductivity type, the collector of said auxiliary transistorbeing coupled to said other of said poles of said source, the emitter ofsaid auxiliary transistor being coupled to said other plate of saidcapacitor and the base of said auxiliary transistor being coupled to thejunction of said driving coil and said first and second resistors; and

an additional transistor having its base coupled to said circuit toproduce said sync signal and its collector-emitter path inserted at agiven point in said circuit arrangement to control the conduction ofsaid driving transistor.

2. A circuit arrangement according to claim I, wherein saidcollector-emitter path of said additional transistor is interposedbetween the base of said driving transistor and said other of said polesof said source. 3. A circuit arrangement for carrying out a method ofsynchronizing a balance system of clocks and wrist- 'watches having anautomatic drive circuit and a given vibration frequency comprising thesteps of: generating a sync signal having a given frequency, one half ofsaid given frequency being slightly different than said given vibrationfrequency of said balance system; controlling by said sync signal theconduction of said drive circuit once per semi-vibration of said balancesystem in such a manner that the more said given vibration frequencydeparts from one half of said given frequency the more the energycontent of a primary pulse produced by said drive circuit is reduced;and producing automatically in said drive circuit a secondary pulsehaving the same polarity as said primary pulse as the energy content ofsaid primary pulse is reduced, the energy content of said secondarypulse being dependent on the energy content of said primary pulse, bothsaid primary pulse and said secondary pulse providing a constant totalenergy content for said drive circuit; said circuit arrangementcomprising:

a circuit to produce said sync signal; a supply voltage source having apositive pole and a negative pole; a balance system; a transistor havingits collector-emitter path coupled to one of said poles of said source;an operating coil for said balance system disposed in thecollector-emitter circuit of said transistor; a control coil for saidbalance system; a self-starting network including a resistor coupledbetween said one of said poles of said source and the base of saidtransistor, and a capacitor coupled in series with said control coil inthe base-emitter circuit of said transistor; and

ing coil and the other of said poles of said source.

1. A circuit arrangement for carrying out a method of synchronizing abalance system of clocks and wrist-watches having an automatic drivecircuit and a given vibration frequency comprising the steps of:generating a sync signal having a given frequency, one half of saidgiven frequency being slightly different than said given vibrationfrequency of said balance system; controlling by said sync signal theconduction of said drive circuit once per semi-vibration of said balancesystem in such a manner that the more said given vibration frequencydeparts from one half of said given frequency the more the energycontent of a primary pulse produced by said drive circuit is reduced;and producing automatically in said drive circuit a secondary pulsehaving the same polarity as said primary pulse as the energy content ofsaid primary pulse is reduced, the energy content of said secondarypulse being dependent on the energy content of said primary pulse, bothsaid primary pulse and said secondary pulse providing a constant totalenergy content for said drive circuit; said circuit arrangementcomprising: a circuit to produce said sync signal; a driving transistorof given conductivity type; a control transistor of a conductivity typecomplementary to said given conductivity type; a balance system; asupply voltage source having a positive pole and a negative pole; adrive coil for said balance system having one end thereof coupled to oneof said poles of said source; a first resistor coupled between the otherend of said drive coil and the collector of said driving transistor; theemitter of said driving transistor being coupled to the other of saidpoles of said source; a capacitor having one plate thereof coupled tosaid one of said poles of said source; a second resistor coupled betweenthe other plate of said capacitor and the junction of said drive coiland said first resistor; the emitter of said control transistor beingcoupled to said other plate of said capacitor; a third resistor and afourth resistor coupled in series between said other of said poles ofsaid source and the junction of said drive coil and said first andsecond resistors; the base of said control transistor being coupled tothe junction of said third and fourth resistors; the collector of saidcontrol transistor being coupled to the base of said driving transistor;an auxiliary transistor of a conductivity type complementary to saidgiven conductivity type, the collector of said auxiliary transistorbeing coupled to said other of said poles of said source, the emitter ofsaid auxiliary traNsistor being coupled to said other plate of saidcapacitor and the base of said auxiliary transistor being coupled to thejunction of said driving coil and said first and second resistors; andan additional transistor having its base coupled to said circuit toproduce said sync signal and its collector-emitter path inserted at agiven point in said circuit arrangement to control the conduction ofsaid driving transistor.
 2. A circuit arrangement according to claim 1,wherein said collector-emitter path of said additional transistor isinterposed between the base of said driving transistor and said other ofsaid poles of said source.
 3. A circuit arrangement for carrying out amethod of synchronizing a balance system of clocks and wrist-watcheshaving an automatic drive circuit and a given vibration frequencycomprising the steps of: generating a sync signal having a givenfrequency, one half of said given frequency being slightly differentthan said given vibration frequency of said balance system; controllingby said sync signal the conduction of said drive circuit once persemi-vibration of said balance system in such a manner that the moresaid given vibration frequency departs from one half of said givenfrequency the more the energy content of a primary pulse produced bysaid drive circuit is reduced; and producing automatically in said drivecircuit a secondary pulse having the same polarity as said primary pulseas the energy content of said primary pulse is reduced, the energycontent of said secondary pulse being dependent on the energy content ofsaid primary pulse, both said primary pulse and said secondary pulseproviding a constant total energy content for said drive circuit; saidcircuit arrangement comprising: a circuit to produce said sync signal; asupply voltage source having a positive pole and a negative pole; abalance system; a transistor having its collector-emitter path coupledto one of said poles of said source; an operating coil for said balancesystem disposed in the collector-emitter circuit of said transistor; acontrol coil for said balance system; a self-starting network includinga resistor coupled between said one of said poles of said source and thebase of said transistor, and a capacitor coupled in series with saidcontrol coil in the base-emitter circuit of said transistor; and anadditional transistor having its base coupled to said circuit to producesaid sync signal and its collector-emitter path inserted at a givenpoint in said circuit arrangement to control the conduction of saidtransistor.
 4. A circuit arrangement according to claim 3, wherein oneend of said operating coil is coupled to the emitter of said transistor,and the collector-emitter path of said additional transistor is coupledbetween the other end of said operating coil and the other of said polesof said source.